Not much really, unless you’re bending or breaking the rules, a white hat approach will mean that SEO shouldn’t be affected. Despite the tired old cries of “SEO is Dead!” doing the usual rounds online, if you’re a publisher of quality content then Hummingbird will make no difference. For SEO professionals, it’s actually a good thing as it helps to weed out the black hats that make outrageous (and unfounded) claims that they can get your site on page one of Google search results within a week.For content publishers and writers, Hummingbird is also a good thing, so long as the content being produced is worthwhile. The algorithm is intended to help get rid of irrelevant content and spam and put more weight on industry thought leaders and influencers.The authorship program goes hand-in-hand with this as it allows Google to find authors that produce high-quality content and rely on them to be ‘trusted’ authors.Link building practices are also affected, as the algorithm seeks to find dodgy practices (such as poor quality guest blogging) by evaluating inbound links in a more complex manner.

Hummingbird is such a subtle update that no one noticed it before Google announced it had shipped a month earlier.

The main thing Hummingbird does is handle queries phrased as questions in a sensible fashion. SEOs have been owning Google for years on queries of this type. It's likely that question-focused content will now rank lower than traditional content.